JP2006093990A - Planar antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar antenna apparatus applicable to a mobile phone or the like by reducing an impedance mismatching loss in a short time in the case that a human body approaches the mobile phone like a speech state or the like. <P>SOLUTION: A planar antenna element 101 is connected to an earth plate 104 at a position of a circumferential edge part of the antenna element at which the resonance frequency can be controlled via a first varactor element means 102 for mainly controlling the resonance frequency. The planar antenna element 101 is connected to the earth plate 104 at a position wherein a voltage standing wave ratio in the resonance frequency can be controlled via a second varactor element means 103 for mainly controlling the voltage standing wave ratio at the resonance frequency. The planar antenna element 101 is connected to a feeder 106 at a feeding section 105. The resonance frequency deviated when the human body approaches the mobile phone in a state of a speech state or the like is adjusted to the operating frequency by controlling the capacitance of the first varactor element means 102 and the second varactor element means 103 so as to reduce a mismatching loss and ensure excellent communication quality. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a planar antenna device, and more particularly to a planar antenna device suitable for application to a wireless communication device such as a mobile phone.

  FIG. 11 shows a plate-like inverted F antenna used for a mobile phone or the like as a conventional example. In this plate-like inverted F antenna, a planar antenna element 1101 and a feed line 1102 are connected at a feed portion 1105.

  This plate-like inverted F antenna includes a short stub 1103 that grounds the antenna element 1101 to the ground plane 1104. In this plate-like inverted F antenna, the resonance frequency is determined by the peripheral length of the antenna element 1101, and the sum of the vertical length (W) and the horizontal length (L) of the antenna element 1101 is 1/4 of the wavelength. Resonates at a frequency of

That is, the antenna element 1101 resonates at a frequency at which the circumference of the antenna element 1101 is ½ of the wavelength. Usually, the antenna dimensions are determined so as to resonate in free space at the used frequency.
As an example, FIG. 12 shows frequency characteristics of the antenna VSWR in free space.

  Note that VSWR is an abbreviation for voltage standing wave ratio, and the smaller this value, the more efficiently power can be transmitted to the next stage circuit. The minimum value of VSWR is 1. Here, the use frequency is 600 MHz, and the VSWR is about 1.1 at the use frequency.

  In the call state, the antenna element and the human body are close to each other, and the impedance deviates from the matching state at the operating frequency, resulting in a mismatching state, increasing mismatching loss and greatly reducing the call quality.

FIG. 13 and FIG. 14 are a diagram showing a call state in a mobile phone from the front of the human body and a diagram from the side.
In the talking state, the mobile phone case 1304 (or 1402) is held by hand, and the receiver sound hole 1306 opened in the case is applied to the ear so that the sound from the receiver can be heard, and the sound reaches the microphone. This is a state in which the casing 1304 (or 1402) is tilted by 60 ° from the vertical direction with respect to the ground so that the microphone sound hole 1307 opened in the casing for easy handling is located at the mouth.

  Further, the distance between the antenna and the human body is the closest distance between the power feeding unit of the antenna and the human head including the ears in a call state. In FIG. 13, the distance between the antenna and the human body is indicated by Sp. is there.

FIG. 15 shows the frequency characteristics of the VSWR when the conventional antenna is in a call state. The resonance frequency of the antenna deviates from the use frequency, and the VSWR at the use frequency is about 21. Patent Document 1 discloses a method for matching a shifted resonance frequency with a use frequency.
JP-A-9-307344

  However, in Patent Document 1, when the VSWR at the resonance frequency is greatly deviated, the VSWR cannot be returned as small as the free space, and a problem arises in that the call quality deteriorates without the mismatch loss being eliminated.

  As an example, FIG. 16 shows the frequency characteristics of the antenna VSWR when the method disclosed in Patent Document 1 is applied. The VSWR at the operating frequency is about 3.2, which is relatively high.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an antenna device that solves the above-described problems, and that can eliminate impedance mismatch caused in the proximity of a human body in a short time and reduce power loss due to impedance mismatch in a wireless communication device such as a cellular phone. It is to provide.

  A planar antenna device according to the present invention includes a planar antenna element, and in a planar antenna in which a resonance frequency is determined based on a perimeter of the antenna element, the resonance frequency can be controlled at a peripheral portion of the antenna element. The first variable capacitance element means that is loaded between the antenna element and the ground plane and mainly controls the resonance frequency, and is loaded between the antenna element and the ground plane at a position where the voltage standing wave ratio at the resonance frequency can be controlled. And second variable capacitance element means for controlling the voltage standing wave ratio mainly at the resonance frequency.

  Here, a detecting means for detecting either the received power or the received sensitivity of the received signal from the antenna element, the first variable capacitance element means and the first variable so that the value detected by the detecting means is maximized. And 2 control means for controlling the variable capacitance element means.

  A detecting means for detecting one of power reflected when power is supplied to the antenna element, a voltage obtained by detecting the reflected power, a reflection coefficient, and a voltage standing wave ratio; and a value detected by the detecting means. It is preferable to include control means for controlling the first variable capacitance element means and the second variable capacitance element means so that the minimum value is minimized.

  In addition, a first detection means for detecting either the reception power or reception sensitivity of the received signal from the antenna element, power reflected when the antenna element is supplied with power, voltage obtained by detecting the reflected power, reflection Second detection means for detecting either the coefficient or the voltage standing wave ratio, and the value detected by the first detection means is maximized, and the value detected by the second detection means is minimized. It is preferable to include control means for controlling the first variable capacitance element means and the second variable capacitance element means.

  According to the present invention, the detection means detects whether the impedance is matched or mismatched, and when the impedance is mismatched, the variable capacitance element means is controlled. The first variable capacitance means can mainly control the resonance frequency, and the second variable capacitance means can mainly control the voltage standing wave ratio at the resonance frequency. By controlling these in combination, an impedance matching state can be obtained, and power loss due to impedance mismatching can be reduced.

  And a storage means for storing the capacitance values of the first variable capacitance element and the second variable capacitance element in which the antenna elements are matched or the voltage giving the capacitance value. When controlling the second variable capacitance element means, it is preferable to perform control using the control information read from the storage means.

  According to the present invention, when the impedance is mismatched, the impedance matching state can be achieved in a short time by controlling the variable capacitance element means using the control information read from the storage means. The power loss due to the mismatch can be reduced.

  Further, the control means completes the control processing of any value detected by the first detection means or the second detection means, and reads other control information corresponding to the control information at that time from the storage means It is preferable to control the value detected by the other detection means using the read control information.

  In addition, the storage unit stores in advance control information for impedance matching of the antenna element with respect to a distance from a human body, and the control unit performs initial control on any control information stored in the storage unit. It is preferable to start the control process as information.

  In this case, the control process is started in a state where the impedance deviation is small, and it is possible to shorten the time required to obtain the impedance matching state.

  In addition, it is preferable to include input means for inputting information on the state of the antenna element or the distance between the antenna element and a human body to the control means by a user.

  According to this configuration, by reading an initial value stored in advance in the storage unit corresponding to the information input by the user, the control process is started with a small impedance deviation, and the impedance matching state The time required to do so can be shortened.

In the planar antenna device of the present invention, it is preferable that, in the above configuration, the variable matching means is a variable capacitor, and the control information is a capacitance value of the variable capacitor.
Preferably, the variable matching means is a variable capacitance diode, and the control information is a control voltage applied to the variable capacitance diode.

  According to this configuration, the variable matching means can be a variable capacitance capacitor or a variable capacitance diode, and can be easily brought into an impedance matching state by being controlled by a capacitance value or a control voltage.

  Preferably, the variable matching means includes a plurality of capacitors having different capacities and a switch means for selectively switching the plurality of capacitors.

  According to this configuration, by selectively switching a plurality of capacitors having different capacitances, the matching capacitance is searched discretely instead of continuously, so that the impedance matching state can be achieved in a short time.

  As described above, according to the planar antenna device of the present invention, the first variable capacitor element means for mainly controlling the resonance frequency is located at the periphery of the planar antenna element at a position where the resonance frequency can be controlled. The second variable capacitor element means for controlling the voltage standing wave ratio at the resonance frequency is loaded between the planar antenna element and the ground plane at a position where the voltage standing wave ratio at the resonance frequency can be controlled. By controlling the capacitance values of the first variable capacitance element and the second variable capacitance element so as to be in the impedance matching state, the impedance mismatch caused in the call state can be eliminated in a short time, and the power due to the impedance mismatch Loss can be reduced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a planar antenna device according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS. 1 to 5 and FIG. FIG. 1 is a diagram showing a configuration of a planar antenna used in the first embodiment according to the present invention.

  In FIG. 1, a planar antenna element 101 is connected to a ground plane 104 via first variable capacitance element means 102 that mainly controls the resonance frequency at a position where the resonance frequency can be controlled at the periphery of the antenna element. .

  Further, the planar antenna element 101 is connected to the ground plane 104 via a second variable capacitor element means 103 that mainly controls the voltage standing wave ratio at the resonance frequency at a position where the voltage standing wave ratio at the resonance frequency can be controlled. Has been. Further, the planar antenna element 101 is connected to the feed line 106 at the feed unit 105.

  Here, the operation of impedance by the variable capacitance element will be described. Here, the use frequency is 600 MHz. In the free space, as shown in FIG. 12, the VSWR at the used frequency is impedance matched to about 1.1.

  From this state, when the phone is in a talking state, the resonance frequency becomes about 524 MHz and the antenna VSWR at the use frequency becomes about 21 as shown in FIG. At this time, by adjusting the first variable capacitance element means 102, the resonance frequency can be adjusted as shown in FIG.

  The resonance frequency is about 524 MHz to 600 MHz. Further, by adjusting the second variable capacitance element means 103, the resonance frequency also slightly changes as shown in FIG. 3, but the voltage standing wave ratio mainly at the resonance frequency can be reduced.

  In FIG. 3, the VSWR at the resonance frequency is about 3.3 to about 1.0. By adjusting these variable capacitance elements in combination, the VSWR of the antenna at the operating frequency can be reduced, and the mismatch loss of the antenna can be reduced.

  FIG. 4 is a diagram showing a circuit block configuration of the planar antenna device according to the first embodiment of the present invention. The planar antenna element 101 illustrated in FIG. 1 is connected to the wireless reception unit 403 via the reception power detection unit 402. The control unit 404 is connected to the received power detection unit 402.

  The wireless reception unit 403 performs reception processing such as A / D conversion, demodulation, and decoding on the signal having the reception frequency fr received by the planar antenna 401. The reception power detection unit 402 detects the power of the signal having the reception frequency fr received by the planar antenna 401, and outputs a voltage value obtained by detecting the reception power to the control unit 404.

  The control unit 404 measures the voltage value obtained by detecting the power of the reception signal output from the reception power detection unit 402, and the first variable capacitance element unit 102 and the second variable variable in FIG. 1 so as to maximize the voltage value. The capacitance values Cr1 and Cr2 of the capacitive element means 103 are controlled. Thereby, impedance matching can be achieved for the planar antenna element 101.

Next, a processing procedure in the control unit 404 will be described.
(1) The voltage value obtained by detecting the received power detected by the received power detection unit 402 is measured, and the value is sent to the control unit 404.
(2) The controller 404 changes the capacitance values Cr1 and Cr2 of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 to change the first variable capacitance element means 102 and the second variable capacitance element. The capacitance values Cr1 and Cr2 of the means 103 are set.
(3) By repeating the above (1) and (2), the control unit 404 performs control processing so that the voltage value detected by the received power detection unit 402 is maximized.
(4) The control process at the reception frequency fr at the time of reception is completed. At this time, the impedance matching state is established at the reception frequency fr.

  As described above, according to the present embodiment, by performing the processing in the control unit 404, as shown in FIG. Thereby, at the time of receiving a call state, it is possible to correct a deviation in impedance, reduce power loss due to mismatch loss, and ensure good communication quality.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a diagram showing a circuit block configuration of the planar antenna device according to the second embodiment of the present invention. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The planar antenna element 101 illustrated in FIG. 1 is connected to the wireless transmission unit 603 via the reflected power detection unit 602. The control unit 604 is connected to the reflected power detection unit 602.

  The wireless transmission unit 603 performs transmission processing such as encoding, modulation, and D / A conversion on a signal transmitted to the communication partner, and transmits the signal after transmission processing from the planar antenna element 101 via the reflected power detection unit 602. Transmit as ft radio waves.

  The reflected power detection unit 602 includes a directional coupler inside, and if an impedance mismatch occurs in the planar antenna element 101 at the time of transmission, reflection occurs at the mismatched portion, and the reflection occurs. The power of the signal is branched by a directional coupler, and the voltage value obtained by detecting the reflected power is measured. The measured voltage value is output to the control unit 604.

  The control unit 604 measures the voltage value obtained by detecting the power of the reflected signal output from the reflected power detection unit 602, and the first variable capacitance element unit 102 and the second variable variable in FIG. 1 so as to minimize the voltage value. The capacitance values Ct1 and Ct2 of the capacitive element means are controlled. Thereby, impedance matching can be achieved for the planar antenna element 101.

Next, a processing procedure in the control unit 604 will be described.
(1) The voltage value obtained by detecting the reflected power detected by the reflected power detection unit 602 is measured, and the value is sent to the control unit 604.
(2) In the control unit 604, the capacitance values Ct1 and Ct2 of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 are changed to change the first variable capacitance element means 102 and the second variable capacitance element. The capacitance values Ct1 and Ct2 of the means 103 are set.
(3) By repeating the above (1) and (2), the control unit 604 performs control processing so that the voltage value detected by the reflected power detection unit 602 is minimized.
(4) The control process at the transmission frequency ft at the time of transmission is completed. At this time, the impedance matching state is established at the transmission frequency ft.

  As described above, according to the present embodiment, by performing the processing in the control unit 604, an impedance matching state is established during transmission. Thereby, at the time of transmission in a call state, it is possible to correct a deviation in impedance, reduce power loss due to mismatch loss, and ensure good communication quality.

<Third Embodiment>
A third embodiment of the present invention will be described with reference to FIG. 1, FIG. 7, and FIG. FIG. 7 is a block diagram showing a circuit configuration of the planar antenna device according to the third embodiment of the present invention.

  The planar antenna element 101 shown in FIG. 1 is connected to the changeover switch 702. The changeover switch 702 is switched to be connected to the wireless transmission unit 704 via the reflected power detection unit 703 during transmission and to the wireless reception unit 706 via the reception power detection unit 705 during reception. The control unit 707 is connected to the reflected power detection unit 703, the received power detection unit 705, and the storage unit 708.

  The wireless transmission unit 704 performs transmission processing such as encoding, modulation, and D / A conversion on a signal transmitted to the communication partner, and the signal after the transmission processing is a planar antenna element via the reflected power detection unit 703 and the changeover switch 702. 101 is transmitted as a radio wave having a transmission frequency ft.

  The reflected power detection unit 703 includes a directional coupler inside, and if an impedance mismatch occurs in the planar antenna element 101 during transmission, reflection occurs at the mismatched portion, and the reflection occurs. The power of the signal is branched by a directional coupler, and the voltage value obtained by detecting the reflected power is measured. The measured voltage value is output to the control unit 707.

  The reception power detection unit 705 detects the power of the signal having the reception frequency fr received by the planar antenna element 101, and outputs a voltage value obtained by detecting the reception power to the control unit 707. The wireless reception unit 706 performs reception processing such as A / D conversion, demodulation, and decoding on the signal having the reception frequency fr received by the planar antenna element 101.

  The storage unit 708 stores in advance the capacitance values (control information) of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 that match impedance with respect to the distance between the antenna and the human body.

  In addition, initial values of the capacitance values of the first variable capacitance element and the second variable capacitance element are stored. As an example of the initial value, the capacitance values of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 that are impedance matched in free space are stored. These values are determined and stored in an experiment before shipping the mobile phone.

  The control unit 707 measures the voltage value obtained by detecting the reflected power output from the reflected power detection unit 703, and based on the measurement result, the voltage value obtained by detecting the reflected power using the capacitance value from the storage unit 708 as an initial value is the minimum. The values Ct1 and Ct2 of the first variable capacitor element means 102 and the second variable capacitor element means 103 in FIG. 1 are controlled so that

  Further, the voltage value obtained by detecting the power of the received signal output from the received power detection unit 705 is measured, and the voltage value obtained by detecting the received power using the capacitance value from the storage unit 708 as an initial value is the maximum based on the measurement result. The values Cr1 and Cr2 of the first variable capacitor element means 102 and the second variable capacitor element means 103 in FIG. 1 are controlled so that Thereby, impedance matching can be achieved for the planar antenna element 101.

  Here, the storage unit 708 will be described more specifically. FIG. 8 is a diagram showing a table of capacitance values of variable capacitance elements that are impedance-matched with respect to the distance to the human body stored in the storage unit 708.

  The capacitance values of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 that are impedance matched with the distance to the human body at the transmission frequency ft are stored. Further, the capacitance values of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 that are similarly impedance matched at the reception frequency fr are stored in advance.

  Here, the capacitance of the first variable capacitance element means 102 at the transmission frequency ft is Ct1, the capacitance of the second variable capacitance element means 103 is Ct2, the capacitance of the first variable capacitance element means 102 at the reception frequency fr is Cr1, and the second variable. The capacity of the capacitive element means 103 is Cr2.

Next, a processing procedure in the control unit 707 will be described.
(1) At the time of transmission, the transmission initial value is read from the storage unit 708, and the first variable capacitance element value Ct1 and the second variable capacitance element value Ct2 are set.
(2) In this state, the reflected power detection unit 703 measures the voltage value obtained by detecting the reflected power, and sends the value to the control unit 707.
(3) In the control unit 707, the capacitance values of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 are changed, and the first variable capacitance element means 102 and the second variable capacitance element means 103 are changed. Capacitance values Ct1 and Ct2 are set.
(4) By repeating the above (2) to (3), the control unit 707 performs control processing so that the reflected power detection unit 703 detects the reflected power to the minimum value.
(5) The control process at the transmission frequency ft at the time of transmission is completed. At this time, the impedance matching state is established at the transmission frequency ft. From FIG. 8, there is a distance to the human body corresponding to the optimum capacitance value at the transmission frequency ft, and at the time of reception, the capacitance value at the reception frequency fr of the distance to the human body is read, and the first variable capacitance element means is used as the initial reception value. The capacitance values Cr1 and Cr2 of the second variable capacitance element means 102 and the second variable capacitance element means 103 are set.
(6) In this state, the received power detector 705 measures the voltage value obtained by detecting the received power, and sends the value to the controller 707.
(7) In the control unit 707, the capacitance values of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 are changed to change the first variable capacitance element means 102 and the second variable capacitance element means 103. Capacitance values Cr1 and Cr2 are set.
(8) By repeating the above (6) to (7), the control unit 707 performs control processing so that the voltage value obtained by detecting the reception power by the reception power detection unit 705 is maximized.
(9) The control process at the reception frequency fr at the time of reception is completed. At this time, the impedance matching state is established at the reception frequency fr.

  As described above, according to the present embodiment, by performing the processing in the control unit 707, the impedance matching state is established at the time of transmission and at the time of reception. Thereby, at the time of transmission and reception of a call state, it is possible to correct a deviation in impedance, reduce power loss due to mismatch loss, and ensure good communication quality.

  Furthermore, in the previous processing method, control processing is started from an initial value having a large difference from the optimum value, and a large amount of processing time is spent until impedance matching. However, when the impedance matching state is established at the transmission frequency ft. By setting the capacitance value at the reception frequency fr corresponding to the capacitance value of the initial value of the control processing at the time of reception, the control processing starts from the initial value with a small difference from the optimum value, and the impedance matching state is set. The time required for the process can be shortened.

  In the above description, the control process at the time of transmission is performed after the control process at the time of transmission. Conversely, the control process at the time of transmission may be performed after the control process at the time of reception. Good.

<Fourth Embodiment>
A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a block diagram showing a circuit configuration of a planar antenna device according to the fourth embodiment of the present invention.

  The planar antenna element 101 is connected to the changeover switch 902. The changeover switch 902 is switched so as to be connected to the wireless transmission unit 904 via the reflected power detection unit 903 during transmission and to the wireless reception unit 906 via the reception power detection unit 905 during reception.

  The control unit 907 is connected to a reflected power detection unit 903, a received power detection unit 905, a storage unit 908, and an input unit 909 that allows a user to input a current state.

  The input unit 909 includes a switch, a button, and the like. When the user switches the switch, the input unit 909 notifies the control unit 907 whether the planar antenna is in a free space or a talking state.

  The storage unit 908 stores in advance the capacitance values (control information) of the first variable capacitance element means 102 and the second variable capacitance element means 103 in FIG. 1 that are impedance matched with respect to the distance between the antenna and the human body.

  The storage unit 908 stores initial values of the capacitance values of the first variable capacitance element means 102 and the second variable capacitance element means 103. As an example of the initial value, the capacitance values of the first variable capacitor element means 102 and the second variable capacitor element means 103 in FIG. 1 that are impedance-matched in free space or in a talking state are stored.

  As the initial value in the call state, an average of the distance between the planar antenna and the human body is obtained by experiments with a plurality of subjects, and a capacitance value for impedance matching with respect to the distance is stored. These values are determined and stored in an experiment before shipping the mobile phone.

  The control unit 907 reads the capacitance value stored in the storage unit 908 according to the content notified from the input unit 909, and uses the read capacitance value as an initial value for control. Note that the processing in the control unit 907 is the same as that in the third embodiment, and thus detailed description thereof is omitted.

  As described above, according to the present embodiment, an impedance matching capacity in a call state is prepared in advance as an initial value, an initial value is selected according to the state, and control processing is performed using the selected initial value. Control processing is started from an initial value having a small difference from the optimum value, and the time required to reach the impedance matching state can be shortened.

<Fifth Embodiment>
A fifth embodiment of the present invention will be described with reference to FIG. In FIG. 10, a planar antenna element 1001 has different capacitance values C11 to C1N as first variable capacitor element means 1002 that mainly controls the resonance frequency at a position where the resonance frequency can be controlled at the periphery of the antenna element. A plurality of capacitors 1007 and a changeover switch 1008 are connected to the ground plane 1004.

  Further, the planar antenna element 1001 has different capacitance values C21 to C21 as the second variable capacitor element means 1003 mainly controlling the voltage standing wave ratio at the resonance frequency at a position where the voltage standing wave ratio at the resonance frequency can be controlled. A plurality of capacitors 1009 having C2N are connected to the ground plane 1004 via a changeover switch 1010.

  The planar antenna element 1001 is connected to the feeder line 1006 in the feeder unit 1005. Here, the switch to be turned on corresponds to the control information.

  The circuit configuration of the planar antenna element according to the fifth embodiment is the same as that of the third embodiment except that a planar antenna using a plurality of capacitors and a changeover switch is used as a variable capacitance element, and thus detailed description thereof is omitted. .

  The processing in the control unit is the same as that in the third embodiment except that the control information stored in advance in the storage unit is turned on, and thus detailed description thereof is omitted.

  As described above, according to the present embodiment, the changeover switch that is turned on in an impedance matching state with respect to the distance between the planar antenna and the human body is stored in advance in the storage unit, and is read from the storage unit during control. By controlling the changeover switch and switching the capacitor to be connected, the capacitance that is in the matching state is searched discretely instead of continuously, so that the time required to reach the impedance matching state can be shortened.

  In each of the above-described embodiments, the reflected power detection unit detects the voltage obtained by detecting the reflected power. However, the present invention is not limited to this, and the reflected power, the voltage obtained by detecting the reflected power, the reflection coefficient, and the voltage standing state. Any of the wave ratios may be detected.

  Further, in each of the above-described embodiments, the power of the received signal is detected at the time of reception. However, the present invention is not limited to this, and either the received signal or the reception sensitivity may be detected.

1 is a configuration diagram of a planar antenna shown in a first embodiment of the present invention. The figure which shows the frequency characteristic of VSWR after adjustment by the 1st variable capacitance element shown in 1st Embodiment of this invention. The figure which shows the frequency characteristic of VSWR after adjustment by the 2nd variable capacitance element shown in 1st Embodiment of this invention. 1 is a circuit block diagram of a planar antenna device shown in a first embodiment of the present invention. The figure which shows the frequency characteristic of VSWR in the telephone call state after adjustment by the 1st, 2nd variable capacitance element shown in 1st Embodiment of this invention. The circuit block block diagram of the planar antenna apparatus shown in 2nd Embodiment of this invention The circuit block block diagram of the planar antenna apparatus shown in 3rd Embodiment of this invention The figure which shows the table of the capacitance value of the variable capacity | capacitance matched with respect to the distance of an antenna and a human body memorize | stored in the memory | storage part shown in 3rd Embodiment of this invention. The circuit block block diagram of the planar antenna apparatus shown in 4th Embodiment of this invention Configuration of planar antenna shown in the fifth embodiment of the present invention Configuration of conventional planar antenna The figure which shows the frequency characteristic of VSWR in the free space of the conventional planar antenna Figure showing the call state from the front of the human body Figure showing the call state from the side of the human body The figure which shows the frequency characteristic of VSWR in the call state of the conventional planar antenna The figure which shows the frequency characteristic of VSWR after applying the method disclosed by patent document 1 in the call state of the conventional planar antenna

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Planar antenna element 102 1st variable capacitance element means 103 2nd variable capacitance element means 104 Ground plate 105 Feed part 106 Feed line 401 Planar antenna 402 Reception power detection part 403 Radio reception part 404 Control part 602 Reflection power detection part 603 Radio transmission part 604 Control unit 702 Switch 703 Reflected power detection unit 704 Radio transmission unit 705 Reception power detection unit 706 Radio reception unit 707 Control unit 708 Storage unit 902 Switch 903 Reflected power detection unit 904 Radio transmission unit 905 Reception power detection unit 906 Radio reception unit 907 Control unit 908 Storage unit 909 Input unit 1001 Planar antenna element 1002 First variable capacitance element means 1003 Second variable capacitance element means 1004 Ground plate 1005 Power supply unit 1006 Power supply line 1007 Capacitor 1008 Switch 1009 Key Capacitor 1010 Switch 1101 Planar antenna element 1102 Feed line 1103 Short stub 1104 Ground plate 1105 Feed section 1301 Planar antenna element 1302 Feed line 1303 Short stub 1304 Case 1305 Feed section 1306 Receiver sound hole section 1307 Microphone sound hole section 1401 Planar antenna element 1402 Body Ct1 Capacity of the first variable capacitance element at the transmission frequency Cr1 Capacity of the first variable capacitance element at the reception frequency Ct2 Capacity of the second variable capacitance element at the transmission frequency Cr2 Capacity of the second variable capacitance element at the reception frequency Ct11 to Ct1N Transmission frequency Capacitance of the first variable capacitance element at Cr11 to Cr1N Capacity of the first variable capacitance element at the reception frequency Ct21 to Ct2N Capacity of the second variable capacitance element at the transmission frequency Cr 1 to Cr2N Capacitance of second variable capacitance element at reception frequency C11 to C1N Multiple capacitors in first variable capacitance portion C21 to C2N Multiple capacitors in second variable capacitance portion W Width of plate-like inverted F antenna L of plate-like inverted F antenna Length Sp Distance between antenna and human body

Claims (11)

Comprising a planar antenna element;
In the planar antenna in which the resonance frequency is determined based on the perimeter of the antenna element,
A first variable capacitor element means, which is loaded between the antenna element and the ground plane at a position where the resonance frequency can be controlled at the periphery of the antenna element, and mainly controls the resonance frequency;
A second variable capacitance element means mounted between the antenna element and the ground plane at a position where the voltage standing wave ratio at the resonance frequency can be controlled, and mainly controlling the voltage standing wave ratio at the resonance frequency;
A planar antenna device comprising: Detection means for detecting either the received power of the received signal from the antenna element or the reception sensitivity;
Control means for controlling the first variable capacitance element means and the second variable capacitance element means so that the value detected by the detection means is maximized;
The planar antenna device according to claim 1, further comprising: Detecting means for detecting any one of the power reflected when the antenna element is fed, the voltage obtained by detecting the reflected power, the reflection coefficient, and the voltage standing wave ratio;
Control means for controlling the first variable capacitance element means and the second variable capacitance element means so that the value detected by the detection means is minimized;
The planar antenna device according to claim 1, further comprising: First detection means for detecting either received power or received sensitivity of a received signal from the antenna element;
Second detection means for detecting any one of the power reflected when the antenna element is fed, the voltage obtained by detecting the reflected power, the reflection coefficient, and the voltage standing wave ratio;
The first variable capacitance element means and the second variable capacitance element means are arranged so that the value detected by the first detection means is maximized and the value detected by the second detection means is minimized. Control means for controlling;
The planar antenna device according to claim 1, further comprising: A storage means for storing a capacitance value of the first variable capacitance element means and the second variable capacitance element means in which the antenna element is in a matching state or a voltage giving the capacitance value;
5. The control unit according to claim 2, wherein the control unit controls the first variable capacitor unit and the second variable capacitor unit using control information read from the storage unit. A planar antenna device according to claim 1.   The control means completes control processing of any value detected by one of the first detection means or the second detection means, and stores the other control information corresponding to the control information at that time 6. The planar antenna device according to claim 5, wherein a value detected by the other of the first detection means or the second detection means is controlled using the control information read from the means. The storage means stores in advance control information in which the antenna element is in a matching state with respect to a distance from a human body,
The planar antenna device according to claim 5 or 6, wherein the control means starts control processing using any control information stored in the storage means as initial control information.   The planar antenna device according to any one of claims 2 to 7, further comprising an input unit configured to input information on a state of the antenna element to the control unit.   9. The planar antenna device according to claim 2, wherein the variable capacitance element means is a variable capacitance capacitor, and the control information is a capacitance value of the variable capacitance capacitor.   9. The planar antenna device according to claim 2, wherein the variable capacitance element means is a variable capacitance diode, and control information is a control voltage applied to the variable capacitance diode.   9. The planar antenna device according to claim 2, wherein the variable capacitance element unit includes a plurality of capacitors having different capacitances and a switch unit that selectively switches the plurality of capacitors. .

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